Impacts of Instrument Limitations on Estimated Raindrop Size Distribution, Radar Parameters, and Model Microphysics during Mei-Yu Season in East China

• Published in: Journal of atmospheric and oceanic technology 2017-05, Vol.34 (5), p.1021-1037
• Main Authors: Wen, Long, Zhao, Kun, Zhang, Guifu, Liu, Su, Chen, Gang
• Format: Article
• Language: English
• Subjects: Accretion; Atmospheric precipitations; Atmospheric sciences; Deposition; Disdrometers; Drop size distribution; Education; Evaporation; Evaporation rate; Forecasting; Heavy rainfall; Instrumentation; Instrumentation/sensors; Instruments; Laboratories; Lasers; Microphysics; OTHER INSTRUMENTATION; Parameter estimation; Parameterization; Parameters; Particle size; Particle size distribution; Physical properties; Precipitation; Radar; Rain; Rain gauges; Raindrop size distribution; Rainfall; Rainfall amount; Rainfall estimation; Remote sensing; Seasons; Size distribution; Storms; Studies; Summer/warm season; Surface observations; Velocity
• ISSN: 0739-0572; 1520-0426
• DOI: 10.1175/JTECH-D-16-0225.1

Instrumentation limitations on measured raindrop size distributions (DSDs) and their derived relations and physical parameters are studied through a comparison of the DSD measurements during mei-yu season in east China by four collocated instruments, that is, a two-dimensional video disdrometer (2DVD), a vertically pointing Micro Rain Radar (MRR), and two laser-optical OTT Particle Size Velocity (PARSIVEL) disdrometers (first generation: OTT-1; second generation: OTT-2). Among the four instruments, the 2DVD provides the most accurate DSD and drop velocity measurements, so its measured rainfall amount has the best agreement with the reference rain gauge. Other instruments tend to miss more small drops ( D < 1 mm), leading to inaccurate DSDs and a lower rainfall amount. The low rainfall estimation becomes significant during heavy rainfall. The impacts of instrument limitations on the microphysical processes (e.g., evaporation and accretion rates) and convective storm morphology are evaluated. This is important especially for mei-yu precipitation, which is dominated by a high concentration of small drops. Hence, the instrument limitations need to be taken into account in both QPE and microphysics parameterization.